Introduction

When it comes to pathology exams, being able to differentiate between melanoma and nevi (moles) can be a game-changer. Understanding the subtle histological differences can help you ace not just your exams, but also your future clinical practice.

Why it Matters in Exams

Melanoma is one of the most aggressive skin cancers, and recognising it early can significantly impact patient outcomes. In exams, you may be presented with histological slides where distinguishing between melanoma and various types of nevi is crucial. Knowing what to look for can save you precious points!

Key Histological Features

• Cellularity: Melanomas typically show increased cellularity compared to nevi. Look for densely packed melanocytes.
• Cell Morphology: Melanoma cells often appear pleomorphic (varied in shape and size), while nevi usually have uniform cells.
• Architectural Patterns: Nevi tend to have a more organised structure, often growing in nests. Melanomas can exhibit irregular growth patterns, including single-cell infiltration.
• Involvement of Dermis: Melanoma often shows vertical growth into the dermis, whereas nevi are generally confined to the epidermis and upper dermis.
• Mitotic Activity: Increased mitotic figures can be seen in melanoma. Look for atypical mitotic figures, which are more common in malignant lesions.

How to Remember It

Here’s a mnemonic to help you remember the key differences:

MELANOMA = M for Mitotic figures, E for Irregular Architecture, L for Pleomorphic cells, A for Increased cellularity, N for Neoplasm (malignant), O for Out of control growth, M for Melanin production variability, and A for Aggressive behaviour.

On the other hand, think of nevi as the “NICE” lesions:

N for Neatly organised structures, I for Infrequent mitotic figures, C for Consistent cell morphology, and E for Epidermal or upper dermis confinement.

Conclusion

As a medical student, mastering the histological distinctions between melanoma and nevi not only aids in your exams but also equips you with vital skills for your clinical career. Practice recognising these features in histological slides, and you’ll be well on your way to becoming proficient in pathology.

For additional practice and resources, explore interactive flashcards and quizzes on Microlab.